Version 2.1.2: Python bindings, OBJ assets support, bugfixes.

PiperOrigin-RevId: 434731612
Change-Id: I0cfda3e7a3d1c72036764986efc252ffa1b8c6b0

python/mujoco/serialization.h

@@ -0,0 +1,72 @@
+// Copyright 2022 DeepMind Technologies Limited
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef MUJOCO_PYTHON_SERIALIZATION_H_
+#define MUJOCO_PYTHON_SERIALIZATION_H_
+
+#include <iostream>
+
+#include <mjtnum.h>
+
+namespace mujoco::python::_impl {
+
+// For now, the serialization format is architecture- and version-dependent:
+// It assumes that the writer and the reader have the same endianess, same
+// numeric value sizes and same struct definitions.
+// It is not safe to load serialized data from another version of MuJoCo or from
+// a machine with a different architecture.
+
+static_assert(sizeof(char) == 1);
+static_assert(sizeof(int) == 4);
+static_assert(sizeof(mjtNum) == 8);
+
+inline void WriteChar(std::ostream& output, char c) {
+  output.write(&c, 1);
+}
+
+inline char ReadChar(std::istream& input) {
+  char c = '\0';
+  input.read(&c, 1);
+  return c;
+}
+
+inline void WriteInt(std::ostream& output, int i) {
+  output.write(reinterpret_cast<char*>(&i), sizeof(int));
+}
+
+inline int ReadInt(std::istream& input) {
+  int i = 0;
+  input.read(reinterpret_cast<char*>(&i), sizeof(int));
+  return i;
+}
+
+inline void WriteBytes(std::ostream& output, const void* src, size_t nbytes) {
+  // Start by writing nbytes itself, so it can be validated at the time of
+  // reading.
+  WriteInt(output, nbytes);
+  output.write(reinterpret_cast<const char*>(src), nbytes);
+}
+
+inline void ReadBytes(std::istream& input, void* dest, size_t nbytes) {
+  size_t actual_nbytes = ReadInt(input);
+  if (actual_nbytes != nbytes) {
+    input.setstate(input.rdstate() | std::ios_base::failbit);
+    return;
+  }
+  input.read(reinterpret_cast<char*>(dest), nbytes);
+}
+
+}  // namespace mujoco::python::_impl
+
+#endif  // MUJOCO_PYTHON_SERIALIZATION_H_